This invention relates to a method of recording latent images for Magnetography, and more particularly to an improvement in a method of recording latent images by the Non Return to Zero system (hereinafter referred to as "NRZ system") magnetic recording method.
For recording magnetic latent images on a surface of a recording drum made of magnetic recording medium, the main scanning is effected around the axis of the drum and the subsidiary scanning is effected along the axis of the drum. The width of each track of the main scanning is equal to the width of the recording head.
After recording the magnetic latent images of the character, a magnetic toner is scattered on the latent images, in order to turn the latent images into visible images, so that the character becomes visible in black color. However, simultaneously with the appearance of the character, fine black lines are often observed along the borderlines between tracks generated by the recording head. This appearance of fine black lines, which is called background stain, is an undesirable phenomenon and has been considered to be unavoidable due to the nature of the NRZ system magnetic recording.
In order to overcome the disadvantages due to the above mentioned phenomenon, according to the present invention, an improvement in the conventional NRZ system magnetic recording method in response to the picture signals representing black and white color makes it possible to prevent the appearance of background stains.